I’m always amused by “we must colonize other planets to save humanity.” Let’s take a serious look at the notion. Firstly, we’re wrecking the one planet we’re actually evolved to live on; what is the chance that we’d cope less inadequately on a planet utterly alien and unsuited to our biological and psychological needs? Secondly, fantasies of escaping to a nice pressurized dome after you’ve trashed your own world is merely a billionaire’s folly; the equivalent of having a panic room to retreat to when your party gets out of hand or when someone breaks in to steal your collection of Patek Philippes and Vacheron Constantins (hopefully our billionaire is wealthy enough to have at least one Tour de I’lle). Thirdly, the sheer hubris of the notion is risible. We’re a stupid little ape species incapable of even the most rudimentary capacity to resolve our problems coherently; clustering a bunch of homo sapiens together in an environment in which the slightest problem would mean mass death is not really a very intelligent thing to consider.
All in all, fantasies of escaping to other worlds will remain just that: fantasies. We’re too foolish, our behaviors far too self-harming, and the magnitude of the technological challenges is simply far vaster than most seem willing to recognize.
And let’s face it: why should we have the right to trash other worlds anyway? Best if we simply exterminate ourselves in the next couple of hundred years and let the Earth slowly recover from the consequences of our seemingly endless folly.